How the Heart Functions

The circulatory system, which is in charge of distributing oxygen, nutrients and waste products throughout the body, revolves around the heart, a crucial organ. The heart works as a muscle pump to keep blood flowing and make sure that oxygenated blood is getting to all the body's tissues and organs. Here is a brief explanation of the heart's operations.

Structure of the Heart

• The heart is a muscular organ located in the chest cavity, slightly to the left of the midline.

• It is divided into four chambers - two atria (upper chambers) and two ventricles (lower chambers).

• The right atrium receives deoxygenated blood from the body, while the left atrium receives oxygenated blood from the lungs.

• The right ventricle pumps deoxygenated blood to the lungs for oxygenation, while the left ventricle pumps oxygen-rich blood to the rest of the body.

Cardiac Cycle

• The heart operates through a repeating sequence called the cardiac cycle, which consists of two phases - diastole and systole.

• Diastole : During this phase, the heart's chambers relax and fill with blood. The atria contract to push blood into the ventricles.

• Systole : This phase involves the contraction of the ventricles. The right ventricle pumps blood to the lungs (pulmonary circulation) and the left ventricle pumps blood to the body (systemic circulation).

Blood Flow

• Deoxygenated blood returns to the right atrium through two large veins, the superior vena cava (from the upper body) and the inferior vena cava (from the lower body).

• The right atrium contracts, forcing blood through the tricuspid valve into the right ventricle.

• When the right ventricle contracts, it sends blood through the pulmonary valve into the pulmonary artery, which carries it to the lungs.

• In the lungs, the blood picks up oxygen and releases carbon dioxide. It then returns to the heart via the pulmonary veins, entering the left atrium.

• The left atrium contracts, forcing blood through the bicuspid (mitral) valve into the left ventricle.

• The left ventricle contracts, pumping oxygen-rich blood through the aortic valve into the aorta, which distributes it to the rest of the body.

Valves

Valves within the heart ensure one-way blood flow. The tricuspid valve and bicuspid (mitral) valve separate the atria from the ventricles, while the pulmonary and aortic valves separate the ventricles from the arteries.

Electrical Control

The heart's rhythmic contractions are controlled by an electrical system. The sinoatrial (SA) node, located in the right atrium, generates electrical impulses that initiate each heartbeat. These impulses travel through the atria, causing them to contract. Then, they pass through the atrioventricular (AV) node and into the ventricles, triggering their contraction.

This ongoing cycle of heart chamber contraction and relaxation makes sure that blood is efficiently circulated throughout the body, giving cells oxygen and nourishment while also eliminating waste items. Different heart disorders and diseases might result from any interruptions in this mechanism.